Update Release Notes Build Step

[dwcullop]

You may want to have a look at https://github.com/reactiveui/actions-common or https://github.com/glennawatson/nustreamdocs for how I generate release notes btw. I moved away from what is happening in this repo to a newer tool

Originally posted by @glennawatson in #1092 (comment)

[dwcullop]

@glennawatson Which one do you suggest? ReactiveUI for consistency?

[glennawatson]

Probably my nustreamdocs since we abstracted reactiveui to make it easier for our 10 or so repos to use all the same build pipes

nustreamdocs is just the one off so easier to follow. It's just the steps where it downloads the globla tools, and generates a note file to pass to gh release.

[glennawatson]

           -   name: Install GitReleaseNoteGenerator
                run: dotnet tool install -g GitReleaseNoteGenerator

            -   name: Generate release notes
                env:
                    GITHUB_TOKEN: ${{ github.token }}
                run: git-release-notes --release-version "${{ steps.ver.outputs.version }}" --output-file release-notes.md

            -   name: Create GitHub Release
                env:
                    GH_TOKEN: ${{ github.token }}
                run: gh release create "${{ steps.ver.outputs.tag }}" --repo "${{ github.repository }}" --title "${{ steps.ver.outputs.version }}" --notes-file release-notes.md ./signed/*.nupkg